Browsing by Subject "Pollen"

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  • Kauppi, Paula; Kukkonen, Anna Kaarina (2017)
    Jos allergiset nuha-, silmä- ja astmaoireet ovat vaikeita vuodesta toiseen tavanomaisesta lääkityksestä ¬huolimatta, IgE-välitteiseen allergiaan voidaan antaa siedätyshoitoa. Yleisimmät hoidon aiheet ovat koivu- ja timoteiallergia. Myös eläimille voidaan siedättää, jos tavanomaisen allergialääkityksen teho on riittämätön eikä kontaktia eläimiin pysty kohtuudella välttämään tai jos jo epäsuora kontakti aiheuttaa oireita. Pistiäisallergia on harvinainen, mutta erityinen siedätyshoidon aihe, sillä ampiaisen tai mehiläisen piston aiheuttama anafylaktinen reaktio voi olla hengenvaarallinen.
  • Dalton, April S.; Finkelstein, Sarah A.; Barnett, Peter J.; Valiranta, Minna; Forman, Steven L. (2018)
    Stratigraphic records from formerly glaciated regions are critical for detailed study of the timing, onset and dynamics of past ice sheets and the palaeoecology of previous ice-free intervals. We examined three stratigraphic sections from an 18-km stretch of the Albany River, Hudson Bay Lowlands, Canada, located at the geographic center for many Late Pleistocene ice sheets. Till characterization and correlation suggest that at least three glacial advances from shifting ice centers within the Labrador sector of the Laurentide Ice Sheet were preserved in these stratigraphic records. Non-glacial units (fluvial, organic-bearing sediments) were constrained via optically stimulated luminescence to two possible periods at ca. 73,000 to 68,000 yr BP and ca. 60,000 yr BP. Boreal and peatland taxa (Picea, Pinus, Poaceae, Betula, Cyperaceae, Sphagnum) dominated the pollen record at each site, whereas plant macrofossils analyzed at one site confirm the local presence of conifer trees (bark, needles, seed wings), bryophytes (largely Scotpidium spp), herbaceous plants (Caryophyllaceae, Carex, Poaceae), and an aquatic setting (e.g. Potamogeton, ephippia of Daphnia spp). Pollen-derived average summer temperature reconstructions suggested that local temperatures at the Albany sites were between 12 and 15 degrees C, which is similar to present-day estimates for the region (14.2 degrees C). Reconstructed annual precipitation estimates were 580-640 mm, which is similar to slightly higher than present-day estimates (564 mm). Non-glacial intervals at the Albany sites likely represent abandoned fluvial environments that supported water-logged peatland biota. Results from this research contribute toward ongoing efforts to constrain ice sheet dynamics over North America during the last glacial cycle (e.g. 71,000-14,000 yr BP) and provide insight into the complex Late Pleistocene palaeoclimate record at the innermost area of the glaciated region.
  • Viinanen, Arja; Viitanen, Hilkka (2020)
    • Ruoka-allergia ilmenee toistuvasti samaan ruokaan liittyvänä iho-, limakalvo-, hengitystie- tai suolisto-oireiluna. • Pelkän suolisto-oireen syy on useammin muu kuin allergia. • Koivun siitepölyallergiaan liittyvät lievät suun limakalvo-oireet hedelmistä, juureksista, palkokasveista ja pähkinöistä ovat tavallisimmat aikuisten ruoka-allergiat. • Pähkinä-, maapähkinä-, äyriäis- ja kala-allergia jatkuvat lapsuudesta aikuisuuteen tai alkavat aikuisena ja voivat aiheuttaa vaikeita oireita. • Maito- muna- ja vilja-allergia ovat lapsuuden allergioita, joista suuri osa paranee ennen aikuisuutta
  • Alenius, Teija; Marquer, Laurent; Molinari, Chiara; Heikkilä, Maija; Ojala, Antti (2021)
    Understanding about regional versus local changes in vegetation is critical in answering archaeological questions, in particular at a time when humans are assumed to have caused higher disturbances at local scales rather than regional scales; this is the case during the Neolithic. The aim of this paper is to assess the impact of Neolithic land use on regional and local vegetation dynamics, plant composition and disturbance processes (e.g. fire) in eastern Fennoscandia. We apply the Landscape Reconstruction Algorithm (LRA) to high-resolution pollen records from three lacustrine sediment cores that cover the Neolithic period. We calculate changes in vegetation composition and the rate of plant compositional change. Fire dynamics are estimated as an indicator of land use, although fire can result from both natural and anthropogenic disturbances. Our results show that during the Early Neolithic, changes were mainly driven by natural and climate-induced factors and vegetation composition and fire activity were similar at both regional and local scales. From ca. 4000bconwards, trends in vegetation and fire dynamics start to differ between regional and local scales. This is due to local land uses that are overshadowed at the regional scale by climate-induced factors. The use of the LOVE model in pollen analyses is therefore very useful to highlight local land uses that are not visible by using REVEALS.
  • Rousi, Matti; Possen, Boy J. M. H.; Pulkkinen, Pertti; Mikola, Juha (2019)
    Silver (Betula pendula) and pubescent birch (B. pubescens) are the two main broad-leaved tree species in boreal forests and Subarctic areas, with great significance for both northern societies and ecosystems. Silver birch has more economical importance as it grows taller, but pubescent birch reaches much further North. The adaptability and genetic diversity of Subarctic birch populations are assumed to derive from inter- and intraspecific hybridization. Southern pollen clouds could in turn increase the adaptability of northern populations to warming climate. In the boreal forest zone of warmer climate, incompatibility reactions may prevent interspecific hybridization and much depends on the synchrony of flowering. Direct in situ observations are, however, mostly lacking and earlier results concerning the spatial and temporal match of flowering phenology between the species are contradictory. Conclusions based on pollen catches may also be biased as the pollen of silver and pubescent birch are notoriously difficult to sort out and the geographical origin of pollen is virtually impossible to determine. Here we employ direct flowering observations and reanalyze old pollen and seed production data, collected along a South-North gradient in Finland, to shed more light on these issues. Our results suggest that interspecific hybridization is an unlikely mechanism of adaptation in silver and pubescent birch as there is no significant overlap in flowering either near Subarctic or in more southern boreal areas (covering latitudes 60-68 degrees N). Long-distance southern gene flow also unlikely has importance in the adaptation of northern populations to a warming climate as heat sum requirements for flowering in northern and southern populations are equal and northern birches are therefore not receptive at the time of southern flowering. Long-term data of pollen and seed production in turn suggest that pubescent birch is more effective in seed production through the whole South North gradient, but increasingly so towards the North. However, it appears that this difference is not due to silver birch flowering and regeneration being more sensitive to interannual variation as earlier suggested. Although there are more factors than reproduction alone that can affect species distributions, these two findings indicate that climate warming may not significantly alter the relative abundances of silver and pubescent birch in Subarctic Fennoscandia.